1. Field of the Invention
This invention relates to a log splitting device which relies upon various aspects of the prior art and offers a novel method for log splitting. The device, more specifically, involves the use of a manually held power jack hammer of the conventional type coupled with unique log splitting attachments which include a solid shaft and a solid log splitting head.
2. Prior Art Statement
The use of fire wood perhaps predates the existence of the use of simple hand tools. As the use of simple hand tools evolved, among other things, they were used for the preparation of fire wood. Eventually, not only was fire wood chopped up, and/or sawed, but larger diameter trees were used and the logs were split. Early log splitting devices included wedge-shaped heads which were pounded into logs using hammers to force the logs to split. Subsequently, ram type shaft, hand powered log splitters came into use. However, for all practical purposes, most people still perform the task with hand tools such as a sledge hammer, maul or other pounding device and a wedge. These wedges take many different shapes, including those with blades and those with points. Eventually, power driven log splitting devices were developed and one involved the use of a giant tapered screw connected to a power source. The screw could attach to the wheel of a vehicle and driven when the wheel was raised above the ground with the log being manually pushed into the screw. Alternative devices included horizontal hydraulic ram type equipment and/or other motor driven ram type log splitters in which the logs were laid on a rack and the splitter was forced to pound into and violently split the logs. Sometimes, these were dangerous due to the magnitude of the force, occasionally causing pieces of the log to fly in all directions. Other types have developed for the purpose of log splitting but none of the type described herein.
U.S. Pat. Nos. Des. 268,807 issued to Michael J. Reynolds, 269,406 issued to Anthony Tremaglio and Philip Kaye and 297,500 issued to Irving Kaplan, all show splitting device or splitting wedge designs which are utilized with a maul or hammer to split logs. These require accurate locating and holding of the wedge to get started, accurate hammering and very forceful hammering for the wedge to be successful, along with the risk of having the wedge fly at the user upon impact, having the hammer or maul misstrike the wedge and ricochet in the direction of the user and requiring very, very substantial muscular power to split many of the desirable hard wood logs into fire wood. Additionally, these devices require the user to have their own means or mechanism for holding the log in place during striking. While this is not generally a problem, the rotation of the log due to the impacts for the hammer or maul not hitting the wedge squarely add another safety problem.
In place of the manual hammer and wedge type of log splitting device, there developed a manual log splitter utilizing a shaft and handle whereby human downward force on a movable section of the device would cause human powered impact of a wedge head to eventually split a log. Thus, U.S. Pat. Nos. 4,429,727 issued to Robert C. Wilson and Des. 269,406 issued to Anthony Tremaglio and Philip Kaye describes such devices. The Tremaglio requires hands to be wrapped around a hollow cylinder and with the palms of the hands vertical, the upward and downward motion to cause the wedge to penetrate and split a log. On the other hand, the Wilson device has handles which are horizontal and the user moves a shaft up and down with an impact block inside a housing by lifting up and pushing down on the handles. In order to alleviate the brut force requirements of these types of prior art devices, there evolved devices which were similar but, instead of using human downward force, utilizes force from a gun powder or similar firing. Thus, U.S. Pat. No. 4,646,799 describes a wood splitting device using the vertical impact of a wedge and shaft located in an outer shaft. However, the power source involves the use of an explosive cap placed in the top housing and screwed in so that the force of the explosion pushes downwardly on the shaft. The difficulty with this prior art involves the serious safety concerns of using an explosive, the problem of the device firing the outer shaft upward to some extent when firing the shaft with the wedge downwardly, as well as problems of holding the device in place during explosion or, in the alternative, relying upon a wedge which is partially set into a log, still requiring brut force and all the safety problems mentioned above. Thus, this last device seems to eliminate the use of pure human power but create very substantial safety in doing so.
As mentioned above, the alternative type of log splitting devices are typically rotational screw type devices or ram type devices which act in a horizontal plane and require substantial set up as well as cost, without eliminating the problems of acute force causing log shattering.
The only prior art which seems to have developed along the lines of a manually operated but power driven device which does not utilize explosives and which does not require the substantial set up of the ram type devices or the screw type devices, is a power driven apparatus described in U.S. Pat. No. 4,669,552. This device involves a power driving apparatus which has horizontal handles and a power source for creating reciprocal motion, as well as a log splitting head which enables the user to hold the device as shown in the figures, in a vertical position with the reciprocal impacting of a log splitting head downwardly on a log. While this prior art seems to be a substantial improvement over the above mentioned prior art, it has short comings in that the device does not have the versatility of a jack hammer and, more significantly utilizes a complex tie-in mechanism for the reciprocal power. It does not allow for interchangability with conventional jack hammer heads and even requires a hollow head with a spring type hook attachment to the inside of the hollow head. On the other hand, the present invention is directed to a log splitting device using a jack hammer with a removable shaft and head whereby the device may be used for all operations which are typically available to a jack hammer owner, simply by substituting the shaft and head, and, could not have the durability or weight in the head itself utilizing a hollow head device. Finally, the complexity of the attachment of the head to the device leaves much to be desired in terms of ease of operation.
Thus, not withstanding formidable prior art in this field, there seems to be no prior art which anticipates or renders obvious the present invention utilizing a power jack hammer in conjunction with interchangable shafts having log splitting, solid metal heads.